In my games combat tends to break out where you least expect it, so on roll20 at least, I like to have maps.
For instance, in taverns in my campaigns so far, they've had to deal with a fishman invasion, a robot T-Rex, bar brawls, mage duels, wrestling matches, murder investigations, Orc feud settling, and some other stuff.
But also just for consistency's sake. It helps give the player a sense of where they are in the place. If you're in your cozy small tavern that has a tiny map, it can give a sense of progress and change when you enter a new tavern map that's four times bigger and has four times as many NPCs in it.
If there's an area that I think would really benefit from the atmosphere of using a big illustration I'll use it anyway, combat be damned. (For instance, in my one campaign with Kirby and Reiu in it, I used such an illustration for some hot springs.)